.\" Copyright (c) 2002-2004 Tim J. Robbins. All rights reserved.
.\" Copyright (c) 1993
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.\" From @(#)multibyte.3	8.1 (Berkeley) 6/4/93
.\" From FreeBSD: src/lib/libc/locale/multibyte.3,v 1.22 2003/11/08 03:23:11 tjr Exp
.\" $FreeBSD: src/lib/libc/locale/mblen.3,v 1.6 2007/01/09 00:28:00 imp Exp $
.\"
.Dd April 11, 2004
.Dt MBLEN 3
.Os
.Sh NAME
.Nm mblen ,
.Nm mblen_l
.Nd get number of bytes in a character
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.Ft int
.Fo mblen
.Fa "const char *s"
.Fa "size_t n"
.Fc
.In stdlib.h
.In xlocale.h
.Ft int
.Fo mblen_l
.Fa "const char *s"
.Fa "size_t n"
.Fa "locale_t loc"
.Fc
.Sh DESCRIPTION
The
.Fn mblen
function computes the length, in bytes,
of a multibyte character
.Fa s ,
according to the current conversion state.
Up to
.Fa n
bytes are examined.
.Pp
A call with a null
.Fa s
pointer returns nonzero if the current locale requires shift states,
zero otherwise.
If shift states are required, the shift state is reset to the initial state.
.Pp
Although the
.Fn mblen
function uses the current locale, the
.Fn mblen_l
function may be passed a locale directly. See
.Xr xlocale 3
for more information.
.Sh RETURN VALUES
If
.Fa s
is
.Dv NULL ,
the
.Fn mblen
function returns nonzero if shift states are supported,
zero otherwise.
.Pp
Otherwise, if
.Fa s
is not a null pointer,
.Fn mblen
either returns 0 if
.Fa s
represents the null wide character, or returns
the number of bytes processed in
.Fa s ,
or returns \-1 if no multibyte character
could be recognized or converted.
In this case,
.Fn mblen Ns 's
internal conversion state is undefined.
.Sh ERRORS
The
.Fn mblen
function will fail if:
.Bl -tag -width Er
.It Bq Er EILSEQ
An invalid multibyte sequence was detected.
.It Bq Er EINVAL
The internal conversion state is not valid.
.El
.Sh SEE ALSO
.Xr mbrlen 3 ,
.Xr mbtowc 3 ,
.Xr multibyte 3 ,
.Xr xlocale 3
.Sh STANDARDS
The
.Fn mblen
function conforms to
.St -isoC-99 .
